Electroosmotic pumps drive polar liquids with flow rates in the range from nL/min to mL/min and pressures of up to ˜680 atm using electric fields. Having no moving parts and being completely silent, these pumps have applications in medical and biological fields including drug delivery, artificial organs, biochemical analysis or bioanalytical applications; in active water management; in hydrogen fuel cells or proton exchange membrane (PEM) fuel cells, including air delivery/displacement in PEM fuel cells, miniature fuel cells and for methanol/water mixture delivery in direct methanol fuel cells (DMFCs); as fluid-driving units for micro-fluid injection analysis (μ-FIA); and for cooling in microchip/microelectronics devices.